I posted this a few threads down but I thought I would put it here in it's own thread. This is a post from a guy on RV.net who had the Blownoutsparkplug dude do his plugs. I think the points about cleaning the carbon and the Lincoln heads are interesting.

I just watched one of the guys at blownoutsparkplug.com replace all ten of my plugs.

Not that big a deal. He spent a lot of time carefully removing things and using a compressor to blow out each hole every step of the way. It took him about 2 hours.

The issue is very plain to me now why there is a spark plug issue. The 4 or 5 threads is plenty to hold the plug. The issue is that Ford had a torque spec that was 14 lt. lbs. Lincoln has the same engine, same heads. Their torque spec was 28 ft. lbs. How many Lincolns do you hear having blown out psark plugs???? Not many. I don't care what anybody or any manual says. 14 ft. lbs. is not tight enough. The plugs start to loosen because they were not tight enough in the first place.

My motorhome with 24,000 miles and the full Banks kit was running fine. But, I just wanted to make certain that my spark plugs were good. So, I hired someoen to change them. Good thing I did! One plug on each side was loose! How can you tell for sure? Well, you use a mirror and a flashlight and you look down into the hole. If the plugs was tight, when you remove the plug, you can see a shiny metal ring where the taper of the plugs sits while installed in the head. If the plug was loose, that metal ring is not shiny silver, but is covered in black carbon.

Now, to hear the experts talk about it. If you just plut a new plug back in the hole with the carbon deposits and torque it to 30 ft. lbs., IT WILL STILL LOOSEN BACK UP! Becuase as the engine heats up, the carbon loosens and you now have a false reading on what you thought you torqued the plugs to.

The secret is to use a custom made wire wheel to buff the carbon off the tapered seat that the plug sits in. Then install the plugs dry (no anti seize) and torque them to 30 ft. lbs. NO, they will not strip out if you torque them to 30 ft. lbs. But, as you install the plug, count the number of revolutions that you can hand tighten the plug. It should be at least 4 to 4 1/2 turns. Any less, and the thread stripping process has already begun on your head.

He pulled the dog house and got as many plugs as he could from each side. Sometimes starting under the hood and finish from in the cab. Not that tough a job. But, he had many specialized tools (extensions, sockets, swivels, etc.) that he made it look easy.

The cost was $400 plus $100 travel if I wanted him to come to me (which I did). He did the job in my driveway. I supplied the air compressor, he supplied everything else. The plugs were Motorcraft SP-479. They have a special nickel coating on the threads that is different from the standard black thread plug that came out of there. It is the only plug he will install.

I'm set. I will never have to deal with this again as I will have long since sold the rig before it will need another plug change.

Good luck.

 

If you are talking about the Town Car, that's a regular 2-valve Romeo motor. They are not the same heads as a V10, that's for sure.

Depending on what year Lincoln it is, there are upgrades to the heads of all 2-valve and 4-valve heads between 1996 and 2003.

December 1996 - 4.6L 4V alignment feature added
February 1997 - 4.6L 2V head alignment feature added
September 2000 - WEP (Windsor Engine Plant) 2V head alignment feature modified (4.6/5.4/6.8)
November 2002 - WEP introduced long thread heads on 2V (all)
May 2003 - REP (Romeo Engine Plant) introduced long-thread heads on 4V 4.6 and 5.4
November 2003 - REP introduced long-thread heads on 2V and modified alignment feature

 

Oh, and 28ft/lbs for what Lincoln vehicle? They aren't all the same.

 

Thanks Krew, I don't know which Lincoln he was talking about, since I am repeating another fellows post. If all the heads are aluminum it makes me wonder if it matters, and if the 28 ft pounds is true, then what could be the deciding difference between a head that needs 168 inch pounds versus 28 ft pounds. Im gonna send the fellow a private message to see if he has any additional information and I will post it here when he answers. Does the Romeo motor have aluminum heads ?

 

Are the Ford heads and the Lincoln heads cast out of the same Aluminum alloy.

Different aluminum alloys have different properties.

I don't agree with not putting anti-seize on the threads. You cannot get an accurate torque reading on dry threads.

I recently changed the plugs on my sisters 95' explorer which has the same plugs as used on earlier modulars, the only difference is she has cast iron head on her 4.0l. Since Ford switch to aluminum heads with the old style plug the problem began.